题解 | a+b

#include<bits/stdc++.h>
using namespace std;
string f(string a,string b)//a是长度大的 
{
	int na=a.size();
	int nb=b.size();
	int jw=0;
	int cha=na-nb;
	//string answer=a;
	for(int i=na-1;i>=0;i--)
	{
		if(i-cha>=0)
		{
			int numa=a[i]-'0';
			int numb=b[i-cha]-'0';
			int current=numa+numb+jw;
			jw=current/10;
			int aaa=current%10;
			a[i]=aaa+'0';
		}
		else
		{
			int numa=a[i]-'0';
			int numb=0;
			int current=numa+numb+jw;
			jw=current/10;
			int aaa=current%10;
			a[i]=aaa+'0';
		}
	}
	if(jw!=0)
	{
		char c=jw+'0';
		a=c+a;
	}
	return a;
 } 
int main()
{
	string a,b;
	cin>>a>>b;
	string ans="";
	if(a.size()>b.size())
	{
		ans=f(a,b);
	}
	else
	{
		ans=f(b,a);
	}
	cout<<ans;
	return 0;
 }